Substituted purines as hypolipidemics

ABSTRACT

The d-isomer of optically active 3-(6-amino-9H-purin-9-yl)-1,2; propanediol is prepared from d-9-((2-substituted and 2,2disubstituted-1,3-dioxol-4-yl)methyl)adenines and both the product isomer and starting materials are useful as hypolipidemic agents.

United States Patent 3,91 1,128

Buzzolini 1 Oct. 7, 1975 1 SUBSTITUTED PURINES AS [56] References Cited HYPOUPIDEMICS UNITED STATES PATENTS Inventor: Mario Buzlolinii Morristown, 3,505,453 4/1970 Thiel et al .2 424/253 [73] Assigngej Sandal, Inc 5 Hanover Ni Primary Examiner-Frederick E Waddell Attorney, Agent, or Firm-Gerald D. Sharkin; Robert [22] Filed: June 24, 1974 Honor [21] Appl. No.1 482,242

Related US. Application Data [57] ABSTRACT {62] Division of Sen No. 224,327, Feb, 7, I972, Pat, No The Chisomer Of Optically active -P 1836,6561 9-yl)-l,2; propanediol is prepared from d-9-[(2 substituted and 2 2-disubstitutedl ,3-di0x0l-4- [52] U.S. Cl. 424/253 y1)methyl]adenines n both h p uct i mer and [5 I 1 Int. Cl. .1 A61K 27/00 starting materials are useful as hypolipidemic agents. [58] Field of Search .1 424/253 2 Claims N0 Drawings SUBSTITUTED PURINES AS HYPOLIPIDEMICS This is a division of application Ser. No. 224.327. filed Feb. 7. 1972. now US. Pat. No. 3.836.656.

This invention relates to the pharmaceutical activity of the d-isomer of substituted purine compounds. More particularly. this invention concerns the use of d-3-(6- amino-9H-purin-9-yl)-l ,Z-propanediol and novel derivatives of this isomer in the treatment of lipidemia in animals. The invention also relates to a process for preparing the isomer from the novel derivatives.

The active agents with which this invention is concerned may be represented by the following structural formula:

where R and R: each represent hydrogen or R and R together represent where R; and R, each independently represent lower alkyl. i.e.. alkyl having 1 to 4 carbon atoms, e.g.. methyl, ethyl. isopropyl and the like or one of R or R, is hydrogen and the other is phenyl The compound of formula I in which R, and R are both hydrogen is known in racemic mixture form. The d-isomer may be isolated from the racemic mixture using standard techniques in addition to being prepared by the procedure described below. The present inven tion comtemplates only the novel use of this compound in pharmaceutical applications. particularly as a hypolipidemic agent.

The d-isomer of the compound of formula (I) in which R, and R are both hydrogen may be prepared in accordance with the following reaction scheme:

(lb) (la) where R and R, are as defined above.

The compounds of formula (la) are prepared by treating the d-isomer of a compound of formula (lb) with an acid in an aqueous solvent. The acid can be a mineral acid such as hydrochloric acid. sulfuric acid, and the like or an organic acid such as acetic acid. trichloroacetic acid and the like. The particular acid used is not critical but hydrochloric acid is preferred. The aqueous solvent can be water or a mixture of water and a water soluble organic solvent. e.g.. the lower alkanols. The preferred solvent is water. although the particular solvent used is not critical. The temperature of the reaction is also not critical. but it is preferred that the reaction be carried out between 20 to 30C. The reaction is normally run for from 2 to 24 hours for optimum results. The product is recovered by conventional techniques. e.g.. crystallization.

The compounds of formula (lb) are novel and may be prepared in accordance with the following reaction scheme:

M is an alkali metal Y is a leaving group and R and R are as defined above The compounds of formula (lb) are prepared by treating a compound of formula (II) with a d-isomer of a compound of formula (III). The alkali metal in the compound of formula (I1) is preferably sodium or potassium. The compounds of formula (II) are prepared by treating adenine with an alkali metalating agent which can be an alkali metal hydride. e.g.. sodium hydride. potassium hydride and the like; an alkali metal amide. e.g.. sodium amide. potassium amide. and the like, an alkali metal aleoholate such as sodium ethanolate or potassium ethanolate or an alkali metal carbonate such as sodium carbonate or potassium carbonate. The particular leaving group used in the compound of formula (III) is not critical and can be a tosylate. mesylate, and the like. preferably a tosylatev Although a solvent is not critical. the reaction is preferably carried out in an inert sol\cnt. for example. dimcthylac' ctaniide. dimethylsulfoxide. dimethylformamidc. henzene. toluene. hexane. and the like. Dimethylformamide is especially preferred. The reaction is preferably run at a temperature of from about 70 to 110C. especially between about 80 to 90C. although the temperature is not critical, The time also is not critical. but for optimum results. the reaction should be run for about 2 to 48 hours. The product is recovered by conventional techniques. e.g.. recrystallization.

The compound of formula (ll) and many of the compounds of formula (lll) are known and may be prepared by techniques described herein in the case of compound (ll) or as disclosed in the literature in the case of compound (Ill). The compounds of formula (Ill) not specifically disclosed in the literature may be prepared by anologous methods using known starting materials.

As previously indicated. the compounds of formula (I are useful because they possess pharmacological activity in animals. particularly as hypolipidemic agents. as indicated by the fall in cholesterol and triglyceride levels in male albino Wistar rats weighing l l()l3() g. initially. The rats are maintained on drug-free laboratory chow diet for seven days and then divided into groups of 8 to It) animals. Each group with the exception of the control is then given orally milligrams per kilogram of body weight per diem of the compound for (1 days. At the end of this period. the animals are anesthetized with sodium hexobarbital and bled from the carotid arteries. Serum or plasma samples are collcctcd. and 1.0 ml samples of the serum are added to 9.0 ml redistilled isopropanol. Two autoanalyzer cupsful of a mixture of zeolitecopper hydroxide and Lloydds reagent (Kcssler. (l. and Lederer, H.. l965. Technicon Symposium. Mediad Inc.. New York, 345-347) are added. and the mixture is shaken for one hour. Cholesterol and triglyceride levels are determined simultaneously on the same sample by Technicon N 24 A (cholesterol) and N-78 (triglyceride) methodology. The mean total serum cholesterol levels are then computed and the hypocholestcrolemic activity is expressed as the fall in cholesterol levels as a percentage of the control level. The change in serum triglyceride levels induced by the drug is computed as a percentage of the control triglyceride levels.

For such usage. the compounds (I) may be administered orally or parenterally as such or admixed with conventional pharmaceutical carriers. They may be administered in such forms as tablets. dispersiblc powders. granules. capsules. syrups and elixirs and paren terally as solutions, suspensions. dispersions. emulsions and the like. eg. a sterile injectablc aqueous solution. The compositions may contain one or more conventional adjuvants. such as sweetening agents. flavoring agents. coloring agents and preserving agents. in order to provide an elegant and palatable preparation. Tablets may contain the active ingredient in admixture with conventional pharmaceutically acceptable excipients. cg. inert diluents. such as calcium carbonate. sodium carbonate. lactose and talc. granulating the disintegrating agents. c.g.. starch and alginic acid. binding agents. eg. statch. gelatin and acacia. and lubricating agents. cg. magnesium tcarate. stcaric acid and talc. The tablets may be uncoated or coated by known techniques to delay disintegration and absorption in thc gastrtv intestinal tract and thereby prmidc a sustained action over a longer period. Similarly. oral liquids. cg. suspensions may contain the active ingredient in admixture with any of the conventional excipients utiliaed for the preparation of such compositions. e.g., suspending agents (mcthylcellulose. tragacanth and sodium alginatc). wetting agents (lecithin. polyoxyethylcne stearate and polyoxyethylcne sorbitan monooleate) and preservatives (ethyl-o-hydroxybenzoate). Capsules may contain the active ingredient alone or admixed with an inert solid diluent. e.g.. calcium carbonate. calcium phosphate and kaolin. The injectable compositions are formulated as known in the art. These pharmaceutical preparations may contain up to about of the active ingredient in combination with the carrier or adjuvant.

The hypolipidemic effective dosage of compounds (l) employed in the alleviation of lipidemia may vary depending on the particular compound employed and the severity of the condition being treated. However. in general. satisfactory results are obtained when the compounds of formula (I) are administered at a daily dosage of from about 0.7 milligrams to about 250 milligrams per kilogram of animal body weight. preferably given in divided doses two to four times a day. or in sustained release form. For most large mammals. the total daily dosage is from about 50 milligrams to about ZUUU milligrams. Dosage forms suitable for internal use comprise from about 12.5 to about 1000 milligrams of the active compound in intimate admixture with a solid or liquid pharmaceutically acceptable carrier of diluent.

The preferred pharmaceutical compositions from the standpoint of preparation and ease of administration are solid compositions. particularly hardfllled capsules and tablets containing from about 50 to 250 milligrams of the active ingredient.

EXAM PLE l d-3( 6-amino-9H-purin-9yl )-l .Z-propanediol Step A: d-9-[ 2.2-dimethyl-l .3-dioxol-4-yl )methyl] adenine The sodium salt of adenine is prepared by stirring a suspension of 8.96 g of adenine and 3.1 g of sodium hydride (in mineral oil) in ml dimethylformamide at 8()85 for 1V2 hrs. To this suspension is added dropwise at 80-85 a solution of l9.0 g of l.2-U- isopropylideneglyccrol-l p-tosylate in [00 ml dimethyformamide. and stirring is continued at the same temperature for 30 hrs. After cooling the solution is evaporated to dryness in vacuo and the resulting residue is treated with 50 ml of water and extracted three times with a mixture of chloroform/methanol (9:1). The organic layers are combined. dried over anhydrous magnesium sulfate and evaporated to dryness. The resulting crude white solids are recrystallized from methylene chloride/methanol yielding white crystals of (1-9- l( 2.2-dimethyl-l .3-dioxol-4-yl )mcthyl adcnine( m.p. 2l()-2l2; [01],, ,=-23.53).

Following the above procedure but using an equivalent amount of l.Z-(l-benzylidencglycerol-lp tosylatc in place of the l .24)- isopropylidcncglyceroll -p-tosylatc used therein. there is obtained d-3[ Z-phcnyll .3-dioxol4- yl )methyl ladcnine.

Step B: 3-( 6-amino-9 H-purin-9-yl )-l .Z-propancdiol A suspension of 5.0 g of 9-[ 2.2dimethyl-l .3-dioxol- 4-yl)methyll-adeninc in 150 ml 0.1 N hydrochloric acid is stirred at 7S8U for 8 hrs. The resulting clear solution is neutralized with Amberlite lR-lStOH) and filtered. The filtrate is evaporated to dryness in \acuo and the white crude residue is recrystallized from ethanol-water yielding white crystals of d-3-(6-amino- 9H-purin-9-yl l ,2-propanediol (mp. 2 l 3-2 14, [01],, ==44.53).

When the above process is carried out using d-3-l 2- phenyl-l,3-dioxol-4yl-methylladenine in place of the d-3-l 2.2-dimethyll .3-diosol-4-yl )methyl ladenine used therein. there is again obtained 3-(o-amino-9H- purin-9-yl l .Z-propanediol.

EXAMPLE 2 Tablets and capsules suitable for oral administration which contain the following ingredients may be prepared by conventional techniques. Such tablets and capsules are useful in treating lipidemia at a dose of one tablet 2 to 4 times a day.

EXAMPLE 3 The following formulations for syrups or elixirs containing an effective amount of active compound may be formulated using comentional methods. The syrup or elixir may be administered at a dosage of one or two tablespoons once or mice a day.

EXAMPLE 4 The following ingredients are dissolved in water for injection. The resulting solution is filtered through an appropriate medium to form a clear solution. and is 5 then autoclaved to render it sterile. The solution may be administered at a dosage of l or 2 millileters once or twice a day.

H] Ingredient Weight (l l d 3-( o-amino-'-JH-purin- J-yl il .2-propanediol IU Sodium alginate 0.5 Buffering Agent as desired Lecithin 0.5 Sodium chloride as desired [5 Water q.s. to 1 ml.

EXAMPLES 5 and 6 Tablets and capsules containing the ingredients indicated below may be prepared by conventional techniques and are useful in treating lipidemia at a dose of one tablet or capsule 2 to 4 times a day.

Ingredient Weight (mg) tablet capsule d-'-)-| l lIl-dimethyll .3-dioxol-4yl 5U 5U methyl ladenine 'l'mgacanth l I) lactose I975 25H corn starch 25 talcum 15 3() magnesium stearate 2.5

EXAMPLE 7 The following formulations for syrups or elixirs con- %5 taining an effective amount of active compound may be formulated using conventional methods. The syrup or elixir may be administered at a dosage of one or two tablespoons once or twice a day.

Sodium Saccharin Percent by Weight syrup elixir methylladenine Buffering System quantity sufficient to adjust pH Sodium Bcnmate 0.1-0.5 0.1-0.5 Flavoring Agent 001-41,. tun-1).: Water 20-40 5-21) Sim le Syrups US P. -70 I) Sorhitol solution I lU-il ZU-oO Certified Dye [1.5-2 ll.52 Alcohol ll IFS-ll) Methyl Paraben [1 0115-11.] Propyl Paraben l) HMS-[LI Sodium Saccharin l) lHH-ILUH 3.9ll.l28

EXAMPLE 8 The folloning ingredients are dissolved in water for injection. The resultin solution is filtered through an appropriate medium to form a clear solution and is then autoclaved to render it sterile. The solution may he administered at a dosage of l or 2 milliliters once or twice a day.

Sodium Alginate BuiTe ring Agent as desired Lecithin 0.5 Sodium L'hloridc as desired \Vater q.s. to 1 ml. 

1. A METHOD FOR TREATING LIPIDEMIA WHICH COMPRISES ORALLY ADMINISTERING TO A MAMMAL IN NEED OF SAID TREATMENT A HYPOLIPIDEMIC EFFECTIVE AMOUNT OF D-9- (2,2-DIMETHYL-1,3DIOXOL-4-YL)METHYL)ADENINE.
 2. A pharmaceutical composition in dosage form useful in the treatment of lipidemia comprising as an active ingredient thereof about 12.5 to about 1000 mg of d-9-((2,2-dimethyl)-1,3-dioxol-4-yl)methyl)adenine, and a pharamaceutically acceptable carrier therefor. 